1. Field of the Invention
The invention relates to a method and to a device for handling a metal strip. The device comprises in particular a coiling device for winding the metal strip to form a coil and a coil stripper car for receiving the coil from the coiling device.
2. Description of the Prior Art
Numerous documents are known in the prior art that deal in general with the topic of handling wound metal strips.
Thus, the unexamined German Patent Application DE 10 2007 051 976 A1 discloses a coiling device and a method for securing the coils in the coiling device. In concrete terms, the unexamined patent application discloses a coiling device for winding the hot rolled strip after the rolling to form a coil. Moreover, a device is disclosed for producing a welded connection, in order to weld the end of the metal strip on the outer circumference of the coil to a winding that is located farther inward. In this manner, the coil is secured and prevented from violently uncoiling.
In the patent application DE 10 2009 060 257.7, which has not been prepublished, a support for a metal coil on a coiling device is proposed, wherein the coil, referred to also as a coil in the English language, is deposited on three support points. A hold-down device for pressing the coil onto the support points is not disclosed; this has the disadvantage that high-strength metal strips that have a strong tendency to uncoil violently cannot be stored absolutely securely on three support points.
The unexamined German Patent Application DE 10 2007 017 383 A1 discloses a device for binding a coil, which is located on a mandrel set in rotation by a driving unit. In order to be able to achieve a secure and reliable hold, even in the case of a coil that has been coiled from thick strips and has a strong tendency to uncoil violently, the document discloses that at least one pressing roller is provided, by means of which the previously bent flat steel strip is guided around the coil, in order to secure the coil against violent uncoiling.
More remote from the subject matter of the invention are the following additional documents, for example: JP 6047438 A, DE 29 01 454, DE 102004029067 A1, EP 1 647 508 A1, DE 19714551 A1, DE 1940426 A, U.S. Pat. No. 5,044,862 A, DE 3 609 086 A1, DE 43 34 582 A1 and DE 2 806 245 A1.
The European Patent EP 1 888 284 B1 discloses a device and a method for removing a sample from a metal strip that has been wound to form a coil. The device according to the invention provides two floor rollers for storing a coil. At least one of the floor rollers is designed so it can be driven by a driving unit. The strip end has to be fixed, particularly in the case of higher strength strips but also in the case of thicker strips, permanently by one of the rollers, in order to prevent undesired violent uncoiling of the coil. Besides the two floor rollers, at least one pressing roller is provided, which contacts the coil at its outside surface, and fixes it with regard to its position. One of the two floor rollers is designed so that it can be lowered, and, after the fixation of the coil, it can be swiveled by the remaining bottom roller and the at least one pressing roller away from the coil. Due to the swiveling away of one of the floor rollers, an enlarged free strip length remains between the remaining floor roller and the pressing roller, as a result of which the local deformation of the strip end is reduced, without any associated risk of violent uncoiling of the coil.
The invention is based on the following closest prior art:
In the production of hot-rolled strips, that is hot rolled metal strips, on hot strip coiling devices, the finished coils are transported at the end of the winding process by means of a coil stripper car out of the coiling device. For this purpose, the coil stripper cars move under the coil when the latter has been completely wound in the coiling device on the coiling mandrel. The typically two supports of the coil stripper car are then raised, and placed from below against the coil on the coiling mandrel in such a manner that the coil then is applied against the two supports, after the coiling mandrel has been contracted and/or pulled out of the eye of the coil. The coil stripper car is used here first for securing the end of the metal strip, by twisting the coil in such a manner on the two supports that the strip end is pressed due to the gravity force of the coil against the support. After such a deposition of the coil on the coil stripper car, the coil is moved to a coil binding device by means of the coil stripper car.
In conventional hot strips, the production of metal strips tends to involve particularly high strengths and strip thicknesses. Said metal strips are used for producing pipe steels, as well as for extremely strong surfaces. If these materials are wound, then a residual tension remains in the coil, which will open the end of the metal strip again. This tendency increases with greater strength and greater strip thickness, and it occurs particularly in the case of small coils of low gravity force and small diameter. Typical coil diameters are 1000-2300 mm.
In such special coils with high internal residual tension, the coil gravity force often is insufficient to secure the end of the metal strip or the coil on the two supports of the coil stripper car. Rather, there is a risk that the coil can no longer be pulled reliably off the coiling mandrel and moved to the binding station. The coil can remain suspended on the coiling mandrel, and lift itself from the coil stripper car or violently uncoil.
Based on this prior art, the problem of the invention is to further develop a device and a method for handling a metal strip so that the handling of the metal strip, particularly of a metal strip with high residual tension is additionally secured, at the time of the transfer from the coiling mandrel to the coil stripper car, as well as during a transport with the coil stripper car.